Carcinoid Tumor

Carcinoid tumors of the appendix are well-differentiated neuroendocrine neoplasms that arise from the enterochromaffin and enteroglucagon cells normally found in the lamina propria. Appendix is the third most common site in the gastrointestinal tract for carcinoid tumors, following small intestine and rectum in frequency. Most tumors are well-circumscribed but not encapsulated, round to oval, yellow-tan in appearance (as shown here) and usually located in the tip of the appendix. The case shown here measured 1.0 cm in diameter. Most tumors are under 1 cm in size and rarely reach beyond 2 cm.